CN102575951A - Method for detecting flow and thermal flow meter - Google Patents
Method for detecting flow and thermal flow meter Download PDFInfo
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- CN102575951A CN102575951A CN2010800478579A CN201080047857A CN102575951A CN 102575951 A CN102575951 A CN 102575951A CN 2010800478579 A CN2010800478579 A CN 2010800478579A CN 201080047857 A CN201080047857 A CN 201080047857A CN 102575951 A CN102575951 A CN 102575951A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/6842—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow with means for influencing the fluid flow
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
- G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P13/00—Indicating or recording presence, absence, or direction, of movement
- G01P13/02—Indicating direction only, e.g. by weather vane
- G01P13/04—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/72—Devices for measuring pulsing fluid flows
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- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Measuring Volume Flow (AREA)
Abstract
The invention relates to a method for operating a thermal flow meter and thermal flow meter, comprising a first sensor with a first heatable resistance thermometer and at least one further second sensor with a second heatable resistance thermometer, wherein a decision coefficient according to the formula DC=(PC1-PC2)/PC1 is calculated, with PC1(t=t1)= P1,1(t1)/(T1,beheizt, ist(t=t1)-TMedium,is(t=t1)) and PC2(t=t2)= P2,2(t2)/(T2,beheizt, ist t=t2)-TMedium,is(t=t2)) with P being the heating capacity recorded by the corresponding resistance thermometers at the times t and the temperature values T, wherein the value of the decision coefficient indicates the flow direction of a measurement medium in the measuring tube.
Description
Technical field
But but the method and a kind of that the present invention relates to a kind of flow and flow direction of the measuring media that is used for being recorded in measuring tube has the heat flux measurement mechanism first heating resistor thermometer and at least the second heating resistor thermometer, that be used to carry out this method.
Background technology
Conventional heat flux measurement mechanism as far as possible equally uses common two temperature sensors; Said temperature sensor is disposed in that to sell the shape metal shell the most frequently be in so-called stinger (stinger) or the fork (prong), and with contact through measuring tube or through the mobile medium heat of pipeline.For commercial Application, these two temperature sensors are installed in the measuring tube usually; Yet temperature sensor can also directly be installed in the pipeline.One of these two temperature sensors are to utilize heating unit heating, so-called active temperature sensor.Heating unit or other electric resistance heater, perhaps, if temperature sensor self is a resistive element, RTD (Resistance Temperature Device) sensor for example, the then conversion through electric power, for example through measure electric current to change, and be heated.Second temperature sensor is so-called passive temperature sensor: the temperature of its measuring media.
Usually, in the heat flux measurement mechanism, but the heating-up temperature sensor is made and between two temperature sensors, has set up fixing temperature difference by so heating.Alternatively, it also knownly provides constant heating power via control module.
If no any flowing in measuring tube, then the function as the time requires constant heat to keep predetermined temperature difference.If the medium that opposite institute will measure is mobile, the mass rate of the medium of flowing through is depended in the cooling that then has been heated temperature sensor basically.Because medium is lower than heated TEMP actuator temperature, so flow media is away from being heated temperature sensor ground transfer heat.Poor in order so in the situation of flow media, between two temperature sensors, to keep fixed temperature, for heated temperature sensor, require the heating power that increases.The heating power that increases is estimating about the mass rate of the medium through pipeline.
If supplied constant heating power on the contrary, then the temperature difference between two temperature sensors is owing to flowing of medium reduces.Then, this actual temp difference is estimating about the mass rate through pipeline or the medium through measuring tube.
Therefore, there is funtcional relationship in the needed heat energy of heating-up temperature sensor with between through pipeline or mass rate through measuring tube.The dependence of heat transfer coefficient of in the heat flux measurement mechanism, having utilized so-called, the mass rate through measuring tube or the medium through pipeline is to confirm mass rate.Can according to trade mark " t-switch ", " t-trend " perhaps " t-mass " obtain the device of operation around this principle from this assignee.
Until now, mainly in the heat flux measurement mechanism, used and had the RTD element that twines platinum filament spirally.In the situation of thin film resistance thermometer (TFRTD), conventionally, the indentation platinum layer by vapour deposition on substrate.On this, apply another glassy layer and protect platinum layer.Compare with the round shape cross section of RTD element, the cross section of thin film resistance thermometer is a rectangle.In resistive element and/or from the heat transmission of resistive element, correspondingly take place via two surfaces of relatively settling, these two surfaces of relatively settling constitute the major part of the total surface of thin film resistance thermometer together.
Summary of the invention
One object of the present invention is to provide a kind of heat flux measurement mechanism, utilizes this device, and the flow direction of measuring media can easily be identified.
But but be used for utilizing the flow of the measuring media that the first heating resistor thermometer and at least the second heating resistor thermometer be recorded in measuring tube and the method for flow direction to realize this purpose through a kind of; Wherein, At least at very first time point and at the second other time point, yet especially at time point t=t
0, t
1, t
2, t
3... t
n, n is a natural number, the temperature T of measuring media
Medium; Actual(t) be able to measure, wherein the first instantaneous heating power P
1,1(t
1But) put absorption, the wherein second heating power P by the first heating resistor thermometer in the very first time
2,2(t
2But) absorbed at second time point by the second heating resistor thermometer,
Wherein but the first heating resistor thermometer is provided for the first measured temperature T of very first time point
1, heating; Actual(t=t
1) and as the heating power P that is absorbed by first resistance thermometer
1,1(t
1), the temperature T of measuring media
Medium; Actual(t
1But) and the temperature T of the first heating resistor thermometer
1, heating; Actual(t
1) function calculate the first FACTOR P C that represents the flow of measuring media through measuring tube
1(t
1),
Wherein but the second heating resistor thermometer is provided at the second time point t
2The second measured temperature T
2, heating; Actual(t
2) and as the heating power P that is absorbed by second resistance thermometer
2.2(t
2), the temperature T of measuring media
Medium; Actual(t
2But) and the temperature T of the second heating resistor thermometer
2, heating; Actual(t
2) function calculate the second FACTOR P C
2(t
2), and
Wherein as the first FACTOR P C
1(t
1) and the second FACTOR P C
2(t
2) function calculate the coefficient of determination; Wherein when the value of the coefficient of determination is higher than the ultimate value in preceding foundation; The value of the coefficient of determination is illustrated in especially the flow of measuring media in measuring tube on first flow direction with the measuring tube parallel axes; And wherein when the value of the coefficient of determination was lower than the ultimate value in preceding foundation, the value of the coefficient of determination was illustrated in the flow of measuring media in measuring tube on second flow direction, and wherein second flow direction and first flows in the opposite direction.
In first of the present invention is further improved, proposed according to formula PC
1(t
1)=P
1,1(t
1)/(T
1, heating; Actual(t=t
1)-T
Medium; Actual(t=t
1)) calculate representative and put t in the very first time
1Measuring media is through the first FACTOR P C of the flow of measuring tube
1(t
1), and according to formula PC
2(t
2)=P
2,2(t
2)/(T
2, heating; Actual(t=t
2)-T
Medium; Actual(t=t
2)) calculate representative at the second time point t
2Measuring media is through the second FACTOR P C of the flow of measuring tube
2(t
2), and wherein according to formula DC=(PC
1-PC
2)/PC
1[%] calculates the coefficient of determination as percentage.
In other further improvement of the present invention, the measured value T in the temperature of very first time point measurement medium has been proposed
Medium; Actual(t
1But) provide by the second heating resistor thermometer, and/or at the measured value T of the temperature of the second point in time measurement medium
Medium; Actual(t
2But) provide by the first heating resistor thermometer.In other further improvement, at very first time point and second time point and/or at the measured value T of the temperature of all time point t measuring media
Medium; Actual(t) by other three-temperature sensor, the 3rd resistance thermometer provides especially.
Therefore, the very first time point and second time point can be that differ from one another or equal.
The embodiment that depends on the heat flux measurement mechanism be used for determining in that the ultimate value of the coefficient of determination of the flow of leading measuring tube equals zero on the first direction or on second direction, otherwise it is in the scope between 29% and 48%.
The first FACTOR P C
1For confirming, flow taken in, and the second FACTOR P C
2Only be used to confirm flow direction.In this way, an option is only to calibrate first sensor.This occupies controlled heating power usually.For example, it is poor between the temperature of the temperature of heated first sensor and measuring media, to set desired temperatures.On the contrary, the voltage of setting before on second sensor, for example being applied to.Second sensor is not controlled.According to formula P (t)=U about instantaneous electric power
2(t)/and R (t), the voltage that heating power depends on the voltage that on resistance thermometer, applies or strides resistance thermometer descends and the resistance of resistance thermometer, and the resistance of resistance thermometer self is then and then be the function of its temperature.Therefore, can set specific heating power and can also set specific voltage the two.Therefore, the calibration of measurement mechanism of the present invention also only is necessary on a flow direction, because the absolute value on another flow direction equates.It strides the voltage drop of resistance thermometer or the voltage that is applied on the resistance thermometer depends on circuit.
In addition; Be used for confirming and/or heat flux measurement mechanism that the control survey medium is used to carry out according to the described method of one of claim 1 to 8 through the flow of measuring tube, has especially been realized the object of the invention through a kind of; This device comprises control/assessment unit, first sensor and second sensor that at least one is other; Said sensor is arranged in the measuring tube at least in part, but wherein first sensor has the first heating resistor thermometer, for example; Resistance thermometer in the first pin shape housing; And wherein but second sensor has the second heating resistor thermometer, the resistance thermometer in the second pin shape housing for example, and wherein this heat flux measurement mechanism has the baffle that in measuring tube, is disposed in the imaginary line; But make the second heating resistor thermometer be basically parallel to the measuring tube axis; Wherein but but the first heating resistor thermometer and the second heating resistor thermometer are arranged in the measuring tube separatedly, but the flow of not disturbed especially by baffle can flow towards the first heating resistor thermometer, this baffle has along the range of longitudinal axis with along the range of vertical axis especially; Wherein this baffle so is arranged in the measuring tube; Make the point of crossing of longitudinal axis and vertical axis be in the imaginary line between the baffle and second sensor, wherein control/the assessment unit and second sensor are so realized, especially by connection like this; Make at particular point in time; Especially during the heating period, when it finishes or at it after soon, the heating power that second resistance thermometer receive to be set, and/or stride second resistance thermometer setting voltage decline perhaps the voltage of setting be applied on second resistance thermometer.This be independent of the temperature of measuring media and be determined the size.According to P=U
2/ R; Heating power depends on the voltage U that on resistance thermometer, applies or strides the voltage U decline of resistance thermometer and the resistance R of resistance thermometer; Self then depends on its Current Temperatures this resistance, this temperature and then depend on the temperature of measuring media and as the behavior of the function of time.
If baffle is a plate, then according to an instance, the point of crossing of longitudinal axis and vertical axis is in vertical axis and the longitudinal axis of center of gravity and plate of plate perpendicular to the measuring tube axis.
In other further improvement, the heat flux measurement mechanism has the 3rd sensor of the temperature that is used to measure measuring media.The 3rd sensor comprises for example the 3rd resistance thermometer in the 3rd pin shape housing; Wherein also in the situation of first sensor; First resistance thermometer is disposed in the first pin shape housing; And wherein also in the situation of second sensor; Second resistance thermometer is disposed in second pin shape housing (9), and first sensor and second sensor and the 3rd sensor be arranged in the measuring tube in parallel to each other and/or with the vertical axis of baffle abreast, promptly therefore the 3rd pin shape housing of second pin shape housing of first of the first sensor pin shape housing and second sensor and the 3rd sensor by in parallel to each other and/or be arranged in the measuring tube abreast with the vertical axis of baffle; The 3rd sensor is also outside the flow of the measuring media that receives the baffle influence especially; For example, be disposed on one side in the measuring tube at plate, make plate longitudinal axis and the 3rd and/or first sensor intersect.
Heat flux measurement mechanism of the present invention uses in the industrial process measuring technique especially, so that measure for example gas and/or liquid.In such kind situation, the regulation that is used for power-limiting frequently is able to make, and for example is used for explosion-proofly, and can be able to satisfy.
Description of drawings
To explain the present invention in further detail based on accompanying drawing and figure thereof now, wherein, in each situation, propose the instance of embodiment.The element that is equal to is endowed the reference character that is equal in the drawings.Figure in the drawing illustrates as follows:
Fig. 1 is in the cross section, the first heat flux measurement mechanism of the present invention;
Fig. 2 be used for Fig. 1, as the coefficient of determination of the function of Reynolds number;
Fig. 3 is in the cross section, further heat flux measurement mechanism of the present invention;
Fig. 4 be used for Fig. 3 embodiment, as the coefficient of determination of the function of Reynolds number;
Fig. 5 heat flux measurement mechanism of the present invention, further;
Fig. 6 be used for Fig. 5 embodiment, as the coefficient of determination of the function of Reynolds number.
Embodiment
Fig. 1 illustrates first form of the embodiment of heat flux measurement mechanism 1 of the present invention.But first heating sensor 2 is placed on plate 12 one sides as baffle.This sensor comprises the first resistance thermometer (not shown) in first housing 8.The central axial line 16 of first housing 8 roughly is on the longitudinal axis 20 of plate 12 here.The vertical axis 19 of plate is basically parallel to the central axial line of these three sensors.
Yet second sensor 3 here and be not used in and measure the flow size, and is but opposite, the confirming of the direction that only helps to flow.Therefore, second sensor 3 also is considered to uncontrolled sensor.In order side by side to calculate the coefficient of preceding two sensors 2,3, be provided with the 3rd sensor 4 that to realize as not heated sensor, because this sensor has the task of current measured value that the temperature of measuring media is provided for the Measuring Time point.The 3rd sensor 4, therefore the 3rd housing 10 is disposed in measuring tube not by in the flow of the measuring media of plate 12 adjustings similarly.Here the 3rd sensor 4 is vertically put with second sensor, 3 conllinear ground with measuring tube axis 15 with the longitudinal axis 20 of plate 12 abreast and respectively.The distance of three sensor 4 vertical with measuring tube axis 15 equals the distance of first sensor 2 to measuring tube axis 15.Here, in this example, the distance vertical with the longitudinal axis of plate 12 20 is identical with the distance of second sensor 3.Yet this distance depends on application and is variable therefore.
In the illustrated instance of embodiment, housing has the structure that is equal to, and promptly they have identical length, identical wall thickness and identical especially diameter usually, this diameter for example equal 1 and 3mm between, the about diameter of 2mm here.The second and the 3rd sensor 3,4 also depends on the thickness of plate 12 consumingly certainly and equals to three times of diameter of housing for example here to the distance of the longitudinal axis 20 of plate 12.The thickness of plate for example is in the scope between the half-sum twice of diameter of housing.Measure with measuring tube axis normal ground, between the sensor therefore between first sensor and second sensor 2 and 3 and between the interval between the second and the 3rd sensor 3 and 4 is the twice that equates basically and for example be in diameter of the housing and ten times here.These distances also directly depend on board size, and special here floor 12 is along the range of longitudinal axis 20, and this range can be between twice and six times of diameter of the housing for example here.Plate 12 is along the size match of range with the resistance thermometer that in sensor, uses of its vertical axis 19.It can also equal the range of plate 12 along its longitudinal axis 20.
Basic difference with respect to the notion of subsequent discussion is, being used for the ultimate value that flow direction surveys is not zero, but is on the contrary between 29% and 48%.
In this instance of embodiment, but heat flux measurement mechanism 1 such as description ground have 2,3,4, two heating sensors 2,3 of three sensors and be used for confirming the sensor 4 of the temperature of measuring media.Yet flow measurement device 1 of the present invention can also utilize only two sensors realizations.These sensors are alternately born being heated and the function of heated sensor not of the temperature of measuring measuring media then.
For all embodiment, the method that is used to operate heat flux measurement mechanism of the present invention provides following method step.
First resistance thermometer of first sensor was heated during the first heating period, and it is fed the heat energy of first quantity, and confirmed by the heating power of first resistance thermometer absorption at very first time point.Additionally, utilize second resistance thermometer of the heat energy of second quantity, and confirm by the heating power of second resistance thermometer absorption at second time point at the second heating period heats, second sensor.At very first time point and also at second time point, exist in the measured value of the temperature of the measuring media in the measuring tube.
Can in the blocked operation of the very first time point and second time point, measure this measured value of the temperature of measuring media through corresponding not heated sensor, perhaps other sensor is set in the measuring media to be used to confirm the temperature at the very first time point and the second point in time measurement medium.In first situation, very first time point is inequality with second time point.In second situation, second time point can be consistent with very first time point, and the heating power of the first sensor and second sensor is side by side confirmed.
With respect to first heating power that is set in very first time point at the temperature value of heated first resistance thermometer of very first time point with in the difference of the measured value of the temperature of very first time point measurement medium.Similarly, be able to form in the temperature of heated second resistance thermometer of second time point with in the difference of the temperature of the measuring media of second point in time measurement, poor in the instantaneous power of second time point, second resistance thermometer divided by this.Therefore, obtained two coefficients at two time points, like above explanation ground, depended on embodiment, these two coefficients can be that be equal to each other or different.
The essential characteristic of this method is, in order to measure the flow size, has only considered first sensor.First coefficient is the coefficient that is reflected in the flow size of very first time point.First heating power can be restricted to for example 256mW owing to explosion-proof reason.Nature, second heating power also correspondingly is restricted then.First heating power is controlled.Usually, be heated and not heated resistance thermometer between the desired temperatures difference be set to for example 10 ° of K.Yet, according to P=U
2/ R, wherein U strides the voltage drop of resistance thermometer and the resistance that R is resistance thermometer, and it also depends on the resistance of resistance thermometer, and said resistance depends on temperature for them.On the contrary, with reference to poor in desired temperatures first sensor or the 3rd sensor, between the second heated resistance thermometer and the corresponding not heated resistance thermometer, second heating power is uncontrolled.For example, it is by having specific size, setting up at the voltage of preceding setting or power peak.
Utilize these two coefficients that so calculate, formed the coefficient of determination.First coefficient is deducted and divided by second coefficient from second coefficient.Nature, it also is possible deducting second coefficient from first coefficient, wherein the result is then divided by first coefficient.Depend on the embodiment of employed heat flux measurement mechanism of the present invention, as one skilled in the art will know that ground, the ultimate value displacement.
Thus, except volume and/or mass rate, can also write down the flow direction of measuring media in measuring tube.
Fig. 2 illustrate be used for the illustrated heat flux measurement mechanism of Fig. 1, as the curve of the coefficient of determination of the function of Reynolds number.The difference of these two flow directions is very clearly because the curve of first flow direction and second flow direction be restricted to clearly each other away from speed range.At first, in the situation that flows very slowly, this structure provides the reliable coefficient of determination.And in this embodiment, the calibration that is used for flow measurement only is necessary on a flow direction that because in the situation of the flow condition that others equate, but first heating sensor is exported identical measured value on two flow directions.The geometric configuration of Fig. 1 make the coefficient of determination scope on the first direction be flowing between 24% and 29% and for being flowing between 48% and 65% on the second direction.Therefore, should confirm ultimate value for high Re number.Confirm that for all flowing velocities the coefficient of determination is unnecessary.
Fig. 3 is illustrated in heat flux measurement mechanism 1 that appear in the plan view, of the present invention.In the first sensor 2 and second sensor 3 of heat flux measurement mechanism 1, in each situation, only show first housing 8 and second housing 9.This cross section with the vertical plane of the central axial line of housing 16,17 in extend, therefore central axial line only is drawn into a little.Arrow 14 illustrates the flow direction of measuring media (not shown) in the measuring tube (not shown).Yet the part that illustrates of heat flux measurement mechanism 1 is arranged in measuring tube in installment state.
Imagination connecting line 18 extends between housing 8 and 9.It is in this example corresponding to the connecting line between first resistance thermometer and second resistance thermometer.Its near normal ground intersects with the central axial line 16,17 of housing 8,9.Baffle, in the heart, in the plane, measuring tube axis 15 is in this plane here in connecting line 18 for the vertical axis 19 of this back veneer 12 and the point of crossing of longitudinal axis 20, and this plane parallel is extended in the central axial line 16,17 of housing 8,9.Because the vertical axis 19 in this expression is vertically dissectd, and therefore as just an appearance, so the expression of vertical axis 19 is consistent with the expression of the point of crossing of vertical and longitudinal axis 19,20.This here side by side is symmetric points.Plate 12 is point-symmetric with this point of crossing.Because this symmetric construction, so only need calibrate heat flux measurement mechanism 1 of the present invention for the flow measurement on a flow direction.But only survey and require the second heating resistor thermometer for flow direction.Plate 12 in this example and measuring tube axis 15 and also and at two housings 8, connecting line 18 between 9 have about 45 ° angle [alpha] thus.
Because simple and clear former thereby unshowned resistance thermometer is arranged in the end or top of housing 8,9 basically, and plate 12 is between the resistance thermometer.Here the 3rd sensor of the temperature of definite measuring media is not shown.This will be disposed in flow measuring tube, measuring media not by plate 12 influences or no longer by in the zone of plate 12 influences.
The notion of this heat flux measurement mechanism 1 is based on two sensors 2,3 and changes and two FACTOR P C as having described the part of the flowing velocity of the measuring media in measuring tube on every side
1And PC
2With the coefficient of determination DC=(PC that flow direction is shown
2-PC
1)/PC
2 Comparison.Plate 12 is divided flow partly, makes first sensor 2 be disposed in the flow of slowing down here.Plate 12 causes the flow stagnation point on plate 12 on the side that first sensor 2 is positioned at.Second sensor 3 is disposed in the flow of acceleration on the contrary.Plate 12 in this example it, on its two ends of range of longitudinal axis 20, have two round shape ends that help flow to quicken.In the situation of the flowing velocity that changes the measuring media in measuring tube, the angle [alpha] of plate 12 can change and fit should be in flowing velocity.
The housing 8,9 of the first sensor and second sensor 2,3 has identical diameter here in this example.Equal about 4.5 times of such diameter here in two central axial lines 16 of housing, distance between 17, and plate 12 have such diameter about 3 times, along it longitudinal axis 20 and about 5 times, along its expansion of vertical axis 19.The thickness of plate 12, thus it, with about 0.5 times of the diameter that equals housing 8,9 the vertical range in plane vertical and that vertical axis 19,20 limits.Round shape plate 12, that mentioned end is formed by the radius with 0.5mm size accordingly.
Fig. 4 illustrates the curve as the coefficient of determination (DC) of the function of Reynolds number (Re), Re=-15000...15000 here.The ultimate value that is used to determine is 0, and no matter flowing is on first direction shown in Figure 3 or no matter flow is in the opposite direction.In the situation that slowly flows, the value that is used for opposite flow direction is closer to each other.In the situation that flows fast, be used to determine that the value of flow direction separates on the contrary largo.
Therefore, second notion for example also has the plate as the flow regulation member.Yet this can be fixedly mounted in the measuring tube, and the angle of it and measuring tube axis is fixed in illustrated instance at least.In two are further improved, but heating sensor places another force and velocity of a current place that is different from other because of structure.In of the present invention, subsequently further improvement, with basic difference in the notion of preceding general introduction be the measurement of stagnating the stream temperature.
Fig. 5 illustrates heat flux measurement mechanism 1 of the present invention with three dimensional constitution.It has three sensors 2,3,4 in measuring tube 21, wherein first sensor 2 has first housing 8 of bending and second housing 9 that second sensor 3 has bending.The 3rd sensor 4 has and in measuring tube 21, is disposed in first housing and second housing 8, the pin shape housing 10 between 9.Resistance thermometer (not shown) here is utilized in heat between housing and the resistance thermometer, so-called or heat bridge or spacer the most frequently and is fastened in the housing 8,9,10.According to the present invention, but the resistance thermometer of the first sensor and second sensor 2,3 is implemented and is installed in the corresponding shell end with type of heating.Housing shaft 24,25,26 is drawn and can be attached to the sensor holder (not shown) from measuring tube 21.The 3rd sensor 4 is measured the temperature of measuring media.
The crooked position of the housing 8,9 of the first sensor and second sensor 2,3 in here be housing shaft 24,25 and the shell end 22 of pin shape, between 23.In this example, bend all has about 90 ° amplitude in each situation.Yet; Housing so is arranged in the measuring tube 21; Win shell end 22 or its central axial line point are directed upwards towards in first party; Here the central axial line of first shell end 22 and measuring tube axis 15 extend abreast and point on the contrary with flow direction 14, and second shell end 23 is relatively directed therewith.If the amplitude of bend will not be 90 ° but for example only 60 ° on the contrary; Therefore then shell end will not extended fully abreast with the measuring tube axis and also will do not pointed to fully on the contrary with flow direction, but on the contrary only durection component will be directed upwards towards in first party.Here, the central axial line of shell end 8,9 is consistent with the measuring tube axis approx.
Ultimate principle is the difference of the thermoflux between stagnation point and wake flow in this embodiment.Directly contrary its of first sensor flows, and second sensor is in the protection.Thermoflux in stagnation point is higher than the thermoflux in protection, and represents the coefficient of the first sensor 2 of flow to be higher than the coefficient of second sensor 3 thus.This transducer arrangements and measuring tube symmetry, this provides following advantage,, only need on one of two directions of pointing out, calibrate heat flux measurement mechanism 1 of the present invention that is.
Shown in Fig. 6 as the curve of the coefficient of determination of the function of Reynolds number.Flowing velocity is fast more, and ultimate value approaches zero more.In the situation of slow flowing velocity, the difference between flow direction is clearly visual.
Reference numerals list
1 heat flux measurement mechanism
2 first sensors
3 second sensors
4 the 3rd sensors
5 first resistance thermometers
6 second resistance thermometers
7 the 3rd resistance thermometers
8 first housings
9 second housings
10 the 3rd housings
11 sensor holders
12 plates
13 cables
14 flow directions
15 measuring tube axis
The central axial line of 16 first housings
The central axial line of 17 second housings
18 connecting lines between the central axial line of the central axial line of first housing and second housing
The vertical axis of 19 plates
The longitudinal axis of 20 plates
21 measuring tubes
22 first shell end
23 second shell end
24 first housing shaft
25 second housing shaft
26 the 3rd housing shaft
27 first direction components
28 third direction components
The direction that 29 first shell end are pointed to
Claims (14)
- But but 1. one kind be used for utilizing the flow of the measuring media that the first heating resistor thermometer and at least one second heating resistor thermometer be recorded in measuring tube and the method for flow direction, wherein at time point t=t 0, t 1, t 2, t 3... t nMeasure the measured value T of the temperature of the said measuring media of representative Medium; Actual(t), wherein at time point t 1The first heating power P 1,1(t 1But) absorbed by the said first heating resistor thermometer, wherein at time point t 2The second heating power P 2,2(t 2But) absorbed by the said second heating resistor thermometer, but the wherein said first heating resistor thermometer is provided at time point t 1The first measured value T of temperature 1, heating; Actual(t 1), and as the heating power P that is absorbed by said first resistance thermometer 1,1(t 1), the temperature T of said measuring media Medium; Actual(t 1But) and the temperature T of the said first heating resistor thermometer 1, heating; Actual(t 1) function calculate the first FACTOR P C of the said measuring media of representative through the flow of said measuring tube 1(t 1), but the wherein said second heating resistor thermometer is provided at time point t 2The second measured value T of temperature 2, heating; Actual(t 2), and as the heating power P that is absorbed by said second resistance thermometer 2,2(t 2), the temperature T of said measuring media Medium; Actual(t 2But) and the temperature T of the said second heating resistor thermometer 2, heating; Actual(t 2) function calculate the second FACTOR P C 2(t 2), and wherein as the first FACTOR P C 1(t 1) and the second FACTOR P C 2(t 2) function calculate the coefficient of determination; Wherein when the value of the said coefficient of determination is higher than the ultimate value in preceding foundation; The value of the said coefficient of determination is illustrated in the flow of the above measuring media of first flow direction in said measuring tube; And wherein when the value of the said coefficient of determination was lower than the ultimate value in preceding foundation, the value of the said coefficient of determination was illustrated in the flow of the above measuring media of second flow direction in said measuring tube, and wherein said second flow direction and said first flows in the opposite direction.
- 2. method according to claim 1,It is characterized in that,According to formula PC 1(t 1)=P 1,1(t 1)/(T 1, heating; Actual(t=t 1)-T Medium; Actual(t=t 1)) calculate representative at time point t 1Said measuring media is through the first FACTOR P C of the flow of said measuring tube 1(t 1),And according to formula PC 2(t 2)=P 2,2(t 2)/(T 2, heating; Actual(t=t 2)-T Medium; Actual(t=t 2)) calculate representative at time point t 2Said measuring media is through the second FACTOR P C of the flow of said measuring tube 2(t 2),And wherein according to formula DC=(PC 1-PC 2)/PC 1Calculate the said coefficient of determination.
- 3. according to claim 1 or 2 described methods,It is characterized in that,At time point t 1The measured value T of the temperature of said measuring media Medium; Actual(t 1But) provide by the said second heating resistor thermometer, and/or at time point t 2The measured value T of the temperature of said measuring media Medium; Actual(t 2But) provide by the said first heating resistor thermometer.
- 4. according to claim 1 or 2 described methods,It is characterized in that,Measured value T in the temperature of the said measuring media of time point t Medium; Actual(t) provide by separate temperature sensor.
- 5. according to a described method in the claim 1 to 3,It is characterized in that,t 1≠t 2。
- 6. according to claim 1,2 or 4 described methods,It is characterized in that,t 1＝t 2。
- 7. method according to claim 2,It is characterized in that,Said extrema is between 25% and 75%.
- 8. according to a described method in the claim 1 to 6,It is characterized in that,At time point t 2But by the second heating power P of said second heating resistor thermometer absorption 2,2(t 2) be but that the voltage decline of fixing and/or stride the said second heating resistor thermometer is fixed.
- 9. one kind is used for confirming and/or the heat flux measurement mechanism (1) of control survey medium through the flow of measuring tube (21); Comprise control/assessment unit, first sensor (2) and at least one second sensor (3); Said sensor is disposed in the measuring tube (21) at least in part; Wherein said first sensor (2) but have the first heating resistor thermometer; And wherein said second sensor (3) but have the second heating resistor thermometer, and wherein said heat flux measurement mechanism (1) has baffle (12), said baffle (12) basic with measuring tube axis (15) but abreast, and the said second heating resistor thermometer conllinear be disposed in the measuring tube (21); But wherein said first heating resistor thermometer and said second resistance thermometer are disposed in the said measuring tube separatedlyIt is characterized in that,Said control/assessment unit and said second sensor (3) are so realized, make said second resistance thermometer receive the heating power of setting and/or stride the voltage that said second resistance thermometer descends and sets at particular point in time at particular point in time.
- 10. heat flux measurement mechanism according to claim 9,It is characterized in that,Said baffle is plate (12).
- 11. according to claim 9 or 10 described heat flux measurement mechanisms,It is characterized in that,Said heat flux measurement mechanism (1) has the 3rd sensor (4) of the temperature that is used for definite said measuring media.
- 12. heat flux measurement mechanism according to claim 11,It is characterized in that,Said first resistance thermometer is disposed in the first pin shape housing (8) and said second resistance thermometer is disposed in the second pin shape housing (9); And said the 3rd sensor (4) has the 3rd resistance thermometer that is disposed in the 3rd pin shape housing (10), and the wherein said first pin shape housing (8) and the said second pin shape housing (9) and the said the 3rd are sold shape housing (10) quilt and be arranged in abreast in the said measuring tube (21) in parallel to each other and/or with the said vertical axis (19) of said baffle (12).
- 13. according to claim 11 or 12 described heat flux measurement mechanisms,It is characterized in that,Said the 3rd sensor (4) intersects with the longitudinal axis (20) of said baffle (12).
- 14. according to one in the claim 11 to 13 described heat flux measurement mechanism,It is characterized in that,Said the 3rd sensor (4) and said baffle (12) have from one times to three times interval of the diameter of said the 3rd housing (10), and/or said first sensor (2) and said baffle (12) have one times to three times the interval from the diameter of said first housing (8) of parallel with the longitudinal axis (20) of said baffle (12), measurement.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102009045956A DE102009045956A1 (en) | 2009-10-23 | 2009-10-23 | Method for detecting the flow and thermal flow meter |
| DE102009045956.1 | 2009-10-23 | ||
| PCT/EP2010/061948 WO2011047898A2 (en) | 2009-10-23 | 2010-08-17 | Method for detecting flow and thermal flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102575951A true CN102575951A (en) | 2012-07-11 |
| CN102575951B CN102575951B (en) | 2015-06-17 |
Family
ID=43796636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201080047857.9A Active CN102575951B (en) | 2009-10-23 | 2010-08-17 | Method for detecting flow and thermal flow meter |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US9046397B2 (en) |
| EP (1) | EP2491353B1 (en) |
| CN (1) | CN102575951B (en) |
| DE (1) | DE102009045956A1 (en) |
| WO (1) | WO2011047898A2 (en) |
Cited By (4)
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| CN107110696A (en) * | 2014-12-19 | 2017-08-29 | 恩德斯+豪斯流量技术股份有限公司 | Thermal type flow measuring apparatus with diagnostic function |
| CN107209043A (en) * | 2014-12-19 | 2017-09-26 | 恩德斯+豪斯流量技术股份有限公司 | Thermal type flow measuring equipment with diagnostic function |
| CN108351241A (en) * | 2015-10-23 | 2018-07-31 | 恩德斯+豪斯流量技术股份有限公司 | Thermal flowmeter and the method for manufacturing thermal flowmeter |
| CN113924465A (en) * | 2019-06-07 | 2022-01-11 | 恩德斯+豪斯流量技术股份有限公司 | Thermal flowmeter |
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| DE102014114848A1 (en) * | 2014-10-14 | 2016-04-14 | Endress + Hauser Flowtec Ag | Thermal flow meter, method for monitoring the drift of a thermal flow meter and method for determining the flow direction |
| DE102014114940A1 (en) * | 2014-10-15 | 2016-04-21 | Endress + Hauser Flowtec Ag | Thermal flowmeter |
| DE102014115305A1 (en) * | 2014-10-21 | 2016-04-21 | Endress+Hauser Flowtec Ag | Thermal flowmeter |
| DE102015118123A1 (en) | 2015-10-23 | 2017-04-27 | Endress+Hauser Flowtec Ag | Thermal flow meter and assembly with a tube and the thermal flow meter |
| DE102015118125B4 (en) | 2015-10-23 | 2022-11-03 | Endress+Hauser Flowtec Ag | Thermal flow meter and assembly with a tube and the thermal flow meter |
| DE102015118131A1 (en) | 2015-10-23 | 2017-04-27 | Endress+Hauser Flowtec Ag | Thermal flow meter and method of making the same |
| DE102015118120A1 (en) | 2015-10-23 | 2017-04-27 | Endress + Hauser Flowtec Ag | Thermal flow meter and assembly with a tube and the thermal flow meter |
| DE102015118130A1 (en) | 2015-10-23 | 2017-04-27 | Endress+Hauser Flowtec Ag | Thermal flow meter and method of making the same |
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Also Published As
| Publication number | Publication date |
|---|---|
| DE102009045956A1 (en) | 2011-04-28 |
| US9046397B2 (en) | 2015-06-02 |
| WO2011047898A2 (en) | 2011-04-28 |
| WO2011047898A3 (en) | 2011-08-25 |
| EP2491353B1 (en) | 2018-10-10 |
| US20120209543A1 (en) | 2012-08-16 |
| EP2491353A2 (en) | 2012-08-29 |
| CN102575951B (en) | 2015-06-17 |
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